CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Ran Yang,Qianqian Chang,Na Li,Hu Yang
Sulfate radical-based advanced oxidation processes have received increasing attention in contaminated water treatment. As an excellent electron donor, microscale zero-valent aluminum (mZVAl) is a promising persulfate (PS) activator. However, the natural oxide layer of mZVAl impedes electron transfer from the core metal. Herein, a composite comprising mZVAl and Fe-bearing clay (mZVAl-NaNAu-2) was obtained through the simple ball milling (BM), which synergistically activates PS for the efficient degradation of various organic contaminants, such as 4-chlorophenol, benzoic acid, nitrobenzene, phenol, and ofloxacin, in water. The sulfate radicals and hydroxyl radicals were the main reactive species but Fe(IV) was minor in this reaction. The BM can cause fracture of the mZVAl powder and promote exposure of the fresh Al 0 surface. Various Fe species in mZVAl-NaNAu-2 at different reaction times were evaluated by extraction experiments, Mössbauer and XPS spectra. Approximately 47.0% of structural Fe(III) was reduced to Fe(II) after BM. The dissolved Fe(II) and structural trioctahedral Fe(II)-Fe(II)-Fe(II) entities were mainly responsible for the homogeneous and heterogeneous activation of PS, and corroded mZVAl acted as an “electron pool” to regenerate the aforementioned Fe(II) species continuously. The mZVAl-NaNAu-2/PS system also presented certain resistance to a natural organic matter and some anions, such as Cl - and NO 3 - . This study provided a new strategy for the efficient removal of organic contaminants from water and also solved the bottleneck of mZVAl in applications due to its dense oxide film.
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高影响因子
CHEMOSPHERE
·
2021
·
IF 7.086
Guo-Qiang Li,Zheng-Yang Huo,Qian-Yuan Wu,Zhuo Chen,Yin-Hu Wu,Yun Lu,Hong-Ying Hu
Recently, ultraviolet light-emitting diodes (UV-LEDs) and chlorine combined system has been employed as an emerging advanced oxidation process . However, UV-LEDs were commonly considered as monochromatic UV sources. In this study, the obvious quantum yields of chlorine photolysis under 265 nm and 280 nm LEDs irradiations were investigated with treating LEDs as polychromatic UV sources. Particularly, Φ obs-poly of HOCl and OCl⁻ for 265 nm LED were found to be 1.50 and 0.70 mol E −1 , respectively, whereas Φ obs-poly of HOCl and OCl⁻ for 280 nm LED were 1.28 and 0.64 mol E −1 , respectively. It was identified that Φ obs-poly were 5.66–14.63 % lower than Φ obs-mono . This suggests that obvious quantum yield using peak emission wavelength would overestimate the true quantum yield. The production of radical species in LED UV/chlorine systems were determined by the degradation of BA , and illustrated by a mathematical model. Different trends were observed for 265 nm and 280 nm LED UV/chlorine systems as pH increased from 5.0 to 10.0. As pH increased, the formation of OH continuously decreased in both 265 nm and 280 nm LED systems. The formation of Cl increased at neutral pH and more Cl and OH were formed due to the higher molar absorbance coefficient at 280 nm. The chlorine dose-dependent effects on radical productions at pH of 5.0, 7.5 and 10.0 were also assessed. At pH of 5.0, OH was the main radical product and had linear correlation with chlorine dose. At pH of 7.5, the productions of OH and Cl showed similar profiles that increased rapidly at low chlorine dosage and then slowed down.
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PubMed
高影响因子
FUEL
·
2021
·
IF 6.609
Qiao Wang,Wanchen Sun,Liang Guo,Shaodian Lin,Peng Cheng,Hao Zhang,Yuying Yan
The laminar burning speed, Markstein length and cellular instability of three oxygenated fuels, polyoxymethylene dimethyl ether 3 (PODE 3 ), dimethyl carbonate (DMC) and n-butanol (NB), were experimentally studied using spherical flame propagation method. Both of the three fuels are potential alternatives for petrochemical gasoline and diesel. Laminar burning speeds and Markstein lengths were measured at ambient pressure and elevated temperature (363 K-423 K) with three extrapolation models including linear and non-linear employed to extract the unstretched flame speed. Onset of flame cellular instability of the three fuels was determined at high pressure (0.5–0.75 MPa) which was favored to the occurrence of cellular instability. Three well-validated mechanisms for PODE 3 , DMC and NB respectively were used to numerically analyze the flame structure and then understand the underlying effect of the molecular structure of oxygenated fuels on laminar flame propagation. Results show that PODE 3 has the highest laminar burning speed among the three, supporting by both thermal effect and kinetic effect. While the laminar burning speed of NB is higher than that of DMC, which is due to the combined effect of thermal factor and kinetic factor. The molecular structure of oxygenated fuels exerts an influence on the laminar flame propagation through the fuel-specific cracking pathway and resulting formed intermediates with different reactivity. The absence of C–C bond within PODE 3 and DMC leads to the formation of substantial oxy-intermediates (CH 2 O) with high reactivity during fuel decomposition. PODE 3 has the most stable flame among the three because of the strong stretching of PODE 3 flame. The flame stability of DMC and NB is approximately similar especially at high initial pressure.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Jiangyong Liu,Rongfei Ye,Jie Shi,Haiyang Wang,Lixia Wang,Panming Jian,Dan Wang
The state-of-the-art of the catalysis area prefers the construction of highly efficient, stable and low-cost catalysts based on facile and green synthesis procedures with biomass as the precursor. In this respect, we report the preparation of uniform Cu nanoparticles embedded nitrogen–doped carbon catalyst assisted by the carbonization of cushaw and Cu salt without additional reagents. Among the series of catalysts, the one pyrolized at 800 °C is a promising candidate for the liquid-phase reduction of nitrobenzene (NB) in the presence of NaBH 4 , showing superior reactivity and robust stability. Both experimental studies and DFT calculations reveal the strong mutual interaction between Cu nanoparticles and neighboring carbon layer accompanied by the interfacial electron transfer and generation of Cu-N x species. This plays a key role in boosting the adsorption and activation of NB molecules. This study provides new insights for the high-value use of abundant and cheap biomass in advanced catalysis, and sheds light on the interfacial catalysis in driving the NB reduction reaction and beyond.
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高影响因子
CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Yu Zeng,Chenhan Xiong,Jingxuan Li,Zhiyong Huang,Guoping Du,Zhaoyang Fan,Nan Chen
Ceramic/polymer composites have great potential to achieve the concomitant enhancement of both dielectric constant and breakdown field while maintaining other superior properties of the polymer matrix , ideal for elastomer sensors, actuators, capacitive energy storage, and many other applications. However, material incompatibility between the ceramic filler and the polymer matrix often leads to void formation , particle aggregation and phase separation, with significantly degraded performance. Herein, through surface modification, co-doped TiO 2 particles were uniformly dispersed and bridged onto the silicone rubber matrix via a silane coupling agent for fabricating composites via mechanical mixing and hot-pressing. The synthesized composites exhibit enhanced dielectric constant, increased from 2.78 to 5.06 when 50 wt% co-doped TiO 2 particles are incorporated. Their dielectric loss is less than 0.001 in a broad frequency range. Theoretical modelling and experimental results reveal that the morphology and dispersion state of co-doped TiO 2 particles were crucial to the dielectric properties of the silicone rubber-based composites. Besides, the composites are thermally stable up to 400 °C. Significantly increased tensile strength (612 kPa) and elongation at break (330%) were obtained for the composite incorporated with 30 wt% co-doped TiO 2 particles, accompanied by a moderate increased elastic module (540 kPa). Such composites have the potential for different applications.
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高影响因子
ADVANCED ENGINEERING MATERIALS
·
2020
·Vol. 23
·期 1
·2000691
·
IF 3.217
Lu Zhu,Xuanru Ren,Xueqin Kang,Ping Zhang,Peizhong Feng,Xiaohong Wang
MoSi 2 coatings are prepared using spent and commercial MoSi 2 powders as raw materials to protect niobium (Nb) substrate by spark plasma sintering (SPS) technique, and the microstructure and oxidation resistance of the coatings at 1500 °C are investigated. Results showed that obvious pores are found in MoSi 2 coating using commercial MoSi 2 (MC coating) after SPS while MoSi 2 coating using spent MoSi 2 (MS coating) is dense with low porosity. (Mo,Nb) 5 Si 3 diffusion layer is generated between MS coating and the substrate with no gap or cracks, showing excellent metallurgical bonding. After long-term oxidation at elevated temperature, pores and exposed Mo 5 Si 3 can be observed in the oxide scale of MC coating, while dense and complete oxide scale is obtained by MS coating. Lowest mass gain (2.78 mg cm −2 ) is acquired by MS coating after oxidation at 1500 °C for 40 h because SiO 2 oxide scale is completely formed on the dense and bentonite-containing coating, blocking the diffusion of oxygen at high temperature. Compared with MC coating, no further oxidation occurs inside the MS coating or substrate, exhibiting better high-temperature oxidation resistance.
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高影响因子
Physica Status Solidi-Rapid Research Letters
·
2020
·Vol. 15
·期 4
·2000563
·
IF 2.291
Xinhua Li,Qingshuang Ma,Ji Dong,Tansir Ahamad,Zongqing Ma
The Nb 3 (Al 1− x Sn x ) superconductor with enhanced critical current density ( J c ) is prepared by the process of mechanical alloying (MA) and subsequent low-temperature sintering and the enhancement mechanism of J c in Nb 3 (Al 1− x Sn x ) is discussed. The analysis of the flux pinning force implies that there is an additional pinning mechanism apart from grain boundary pinning in Nb 3 (Al 1− x Sn x ). The existence of dispersed Nb 2 Al nanoparticles (<30 nm) in Nb 3 (Al 1− x Sn x ) is confirmed by microstructure observation. These nanosized Nb 2 Al particles can serve as flux pinning centers, which leads to the increase of the flux pinning force as well as the enhancement of Nb 3 (Al 1− x Sn x )'s J c performance.
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高影响因子
MACROMOLECULAR CHEMISTRY AND PHYSICS
·
2020
·Vol. 221
·期 12
·2000085
·
IF 2.335
Zhigeng Chen,Sen Zhang,Qi Feng,Yancheng Wu,Shumei Liu,Jianqing Zhao
Both the formation of insoluble salt for aliphatic diamines and the poor reactivity for aliphatic dianhydrides result in semi-aromatic polyimide (SAPI) with low molecular weight and, thereby, in highly brittle SAPI films in nature. To solve the above problems, a cyclic-olefin copolymer synthesized from norbornene and maleic anhydride is used as the third monomer (crosslinking agent) to prepare the crosslinked SAPI (cSAPI) films. The relative viscosity of the precursor solution of cSAPI is increased with the loading of cyclic-olefin copolymer, giving rise to the improvement in mechanical and thermal properties of cSAPI films. The tensile modulus, tensile strength, and elongation at break of cSAPI film with 5 wt% cyclic-olefin copolymer are increased to 4.49 GPa, 137 MPa, and 14.9% from 3.57 GPa, 111 MPa, and 7.6%, respectively, compared to those of the baseline SAPI film. Meanwhile, the glass transition temperature of cSAPI films is increased to 282 from 270 °C of the SAPI film, which is advantageous to better meet the requirement for high-temperature manufacturing processes such as lead-free solder reflowing. In addition, all cSAPI films exhibit good optical transparency in the entire visible region.
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高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2020
·
IF 5.065
Tong-wei Zhang,Yong-xiang Li,Duan-lin Cao,Yong-zheng Liu,Jia-yuan He,Cheng-long Zou
In this paper, the solubility of 5,5′-bis(2,4,6-trinitrophenyl)-2,2′-bis(1,3,4-oxadiazole) (TKX-55) was first determined by a dynamic laser monitoring at T = (293.15, 298.15, 303.15, 308.15, 313.15, 318.15, 323.15, 328.15 and 333.15) K in fourteen pure solvents, including nitrobenzene (NB), methylethylketone (MEK), dimethyl carbonate (DMC), N,N-dimethylformamide (DMF), methoxybenzene (MOB), ethenyl acetate (VAC), 1,2-propanediol (PDO), cyclohexanone (CYC), epichlorohydrin (ECH), 1-butanol (NBA), n-butyl acrylate (BA), dimethyl sulfoxide (DMSO), tributyl phosphate (TBP) and 2-butanol (IBA), under atmospheric pressure ( P = 0.1 MPa). Besides, supersolubility as well as the metastable zone width of TKX-55 in PDO, BA, DMSO and IBA was determined by the dynamic laser monitoring method. The experimental results showed that the solubility of TKX-55 in fourteen pure solvents increases with increasing temperature and the metastable zone width decreases with increasing temperature. The metastable zone width is approximately 2.49 K–43.26 K. In addition, in order to improve the applicability of the solubility, the modified Apelblat equation, λh equation, the polynomial empirical equation, van't Hoff equation and NRTL equation were used to correlate the solubility data of TKX-55, and the results showed that all models can give a satisfactory correlation. The average root-mean-square deviation (10 2 RMSD) values were 1.71, 8.91, 2.33, 6.12 and 3.30, respectively. Moreover, Hansen solubility parameter was used for explaining the solubility order of TKX-55 in selected solvents, the consequences showed that solubility order of TKX-55 resulted from the comprehensive function of several solubility parameters. The solubility parameter of Δ δ t between TKX-55 and solvents reached from 1.27 MPa 0.5 to 15.28 MPa 0.5 . Furthermore, three kinds of thermodynamic properties of the mixing enthalpy ( Δ mix H ), the mixing entropy ( Δ mix S ) and the mixing Gibbs energy ( Δ mix G ) of TKX-55 in selected solvents were calculated by NRTL equation and the results turned out that the dissolution process was spontaneous. Besides, thermal properties of TKX-55 were measured by differential scanning calorimetry (DSC). The results showed that the melting temperature and the fusion enthalpy were 640.65 K and 19.60 kJ·mol −1 , respectively. Finally, solubility values and thermodynamic relations of TKX-55 in fourteen pure solvents would be invoked as fundamental data and models regarding the purification process.
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高影响因子
JOURNAL OF MATERIALS RESEARCH
·
2019
·Vol. 34
·期 24
·4045-4055
·
IF 1.982
Bo-Qiong Li,Xin-Cheng Li,Xing Lu
In recent years, there has been a significant thrust toward the development of novel implant alloys based on β-Ti with low Young’s modulus to prevent stress shielding. In this study, porous Ti–Nb–Ta–Zr alloys with porosity of <55% and macro-pore size of 100–400 μm for biomedical applications were successfully fabricated by a space-holder method. The microstructure and compressive behavior were studied. The results show that the micro-pore size of porous Ti–Nb–Ta–Zr alloys decreases with an increase in the amount of the process control agent (PCA), which has no obvious effect on the porosity and the macro-pore size formed by the space holder. Porous Ti–Nb–Ta–Zr alloys fail mainly because of the cleavage and ductile fracture with some dimples in compression. The compressive modulus increases from 0.6 to 6.5 GPa with the increase in the PCA and decrease of the space holder. The influence mechanism has been analyzed by the finite element calculation and the Gibson–Ashby model.
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高影响因子
COMBUSTION SCIENCE AND TECHNOLOGY
·
2023
·
IF 1.9
Chen Dong,Yi Wang,Xiaolan Song,Zhipeng Cheng,Chongwei An
The nanometer boron (nB) powders have become the most promising high-energy additive in the field of fuel-rich solid propellants due to their extremely high gravimetric and volumetric calorific value. However, further applications are limited by its disadvantages such as easy agglomeration, easy oxidation, high ignition temperature, and incomplete energy release. Herein, nB powders were pre-agglomerated into microspheres by electrostatic spray method using fluoropolymer (F2602) as binders. The morphology and structure of the samples were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray energy spectrometry (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (IR), and Brunauer-Emmett-Teller (BET). Results showed that the pre-agglomerated nB microspheres had good dispersion, high sphericity, and no surface oxide. The thermal performance and combustion performance of the samples were characterized by a synchronous thermal analyzer and combustion pressure test device. Results showed that the nB microspheres had the highest oxidation weight gain within 1000°C and lowest activation energy compared to the same scale micron boron. In addition, the microspheres significantly shorten the combustion time and improve the combustion efficiency.The pressurization rate of nB microspheres is 4.12 times that of micron boron powders and 2.85 times that of nB powders. These excellent properties may be related to its unique spherical porous structure. Therefore, the preparation of nB microspheres with controllable structure by electrostatic spraying has a good application prospect.
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高影响因子
Crystals
·
2023
·Vol. 14
·期 1
·14
·
IF 2.7
Yufei Zu,Zi Wang,Hongliang Tian,Fan Wu,Lianshen Fu,Jixiang Dai,Jianjun Sha
High-entropy diboride-based (MeB2-based) ceramics are promising high-temperature structural materials because of their excellent mechanical properties, high-temperature stability, and oxidation resistance. In order to achieve low-temperature sintering of the high-entropy ceramics, a novel preparation method of high-entropy (Ti,Zr,Nb,Mo,W)B2-SiC ceramics based on reactive sintering of pre-alloyed solid-solution metals and nonmetals of Si, C, B4C was conducted in the current work. Mechanical alloying behavior of the mixed metal powders, as well as the phase composition, microstructure, mechanical properties, and oxidation behavior of the as-sintered MeB2-SiC ceramic were investigated. The XRD, SEM, and EPMA results indicated that the primary MeB2solid-solution and SiC phases could be successfully formed during reactive sintering at a relatively low temperature of 1650 °C. The as-sintered MeB2-SiC ceramics had a high relative density of 97.8% and high mechanical properties (hardness of 19.74 ± 0.8 GPa, flexure strength of 533 ± 38 MPa, and fracture toughness of 6.01 ± 0.77 MPa·m1/2). Combining the oxidation behavior and microstructure evolution of the oxidation layer, a continuous and relatively dense MeOx-SiO2oxidation layer was gradually formed and covered on the external surface, leading to decelerating oxidation behavior after an oxidation exposure time of 10 min.
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高影响因子
危险品化学品经营许可证（带存储）